1. Destination-less navigation :
2. Foreign-language street names : Currently when speaking out navigation instruction, the whole sentence string is passed as-is to the speech engine. Which usually gives rise to "To turn right into {completely garbled name }" (e.g.: last week I was vacationing in Portugal, and the English text-to-speech engine was unable to meaningfully handle the local names). It's probably going to be even worse if the street names aren't even written in latin script. In case of using an engine that supports multiple language (like pico with english, german, etc.), would it be possible to flag the street names as the foreign language so that the correct "text-to-phoneme" processor handles it ? I'm almost sure that the openstreet maps data has the necessary tagging for that. The question is : does the speech engine support tags to mark different languages (I haven't been playing with TTS engine for at least a decade) ? Alternative fallbacks would be to generate and concatenate the different parts separately (one separate job on the TTS engine for each separate language block) while using correct punctuation to avoid having the intonation mark an end of sentence. (pico.say("Turn left into...", "en-US"); pico.say("Hautpbahnhofstrasse.", "de-DE"); ) Another alternative would be to check which speech engine exposes the text-to-phoneme step separately (the one I used I long time ago did), to concatenate them at the phoneme step, and hope that the final phoneme-to-audio engine will be able to manage all the diverse phonemes.